Agreed that the script should at the very least test that the command exists first.

Tangentially related: for  issue 784651 , I was about to update chromeos_startup to create a lockfile directory that'll soon by used by flashrom:

https://crrev.com/c/886831
https://crrev.com/c/809853

I can give some story here.

In the very beginning I did plan to detect and run, as something like

 if [ -x /usr/sbin/firmware-boot-update ]; then
   /usr/sbin/firmware-boot-update
 fi

But the code reviewers (Mike?) suggested it's better to always have the file (and be empty if no boot update needed) - faster in execution, easier to understand and similar boot path. So I changed the implementation to simply "/usr/sbin/firmware-boot-update" with comments that most files should be zero.

However, the file is decided by chromeos-firmware-* ebuild package. It's usually in private overlays, and the public overlay was using a dummy ebuild file. Since all "real" chromeos should have firmware ebuilds in private overlay, we didn't spend too much time fixing this.

Now back to the issue. I'm fine if you want to change to chromeos-base/chromeos-firmware in public overlay to include that dummy file. But watch out - then you have to pay attention when creating chromeos-firmware-$BOARD in overlay, since files prepared by two different ebuild packages will cause conflict, and it's usually hard for partners or many googlers (who need to make contribution to the ebuild files) to figure out what to do. It seems to me leaving some error message in an unofficial build image is not a big deal, in comparison to the ebuild migration issues.

Ick.  I definitely don't want to screw around with having two different ebuilds providing the same file.  That's always a hassle.

...so it sorta sounds like this is by design and people want to keep it that way.  If that's true, I guess I'd at least prefer to change the comment to indicate that.

changing the comment sounds great, maybe even with a link to this issue :)

https://chromium-review.googlesource.com/c/chromiumos/platform2/+/902457

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/d66fbc595e21a93ebf5a98441f8b18f53f67bc83

commit d66fbc595e21a93ebf5a98441f8b18f53f67bc83
Author: Douglas Anderson <dianders@chromium.org>
Date: Tue Feb 06 23:41:23 2018

init: chromeos_startup: Add a comment about firmware-boot-update

I recently got confused and spent a little time debugging why
firmware-boot-update didn't exist on my board, only to find that the
error was non-fatal.

Add a comment to avoid future confusion.

BUG= chromium:806383 
TEST=Put this on a board and see that it still boots

Change-Id: Ia91c3339b0be29c01e1e61b330281c71e2b36211
Reviewed-on: https://chromium-review.googlesource.com/902457
Commit-Ready: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[modify] https://crrev.com/d66fbc595e21a93ebf5a98441f8b18f53f67bc83/init/chromeos_startup

after firmware-boot-update is dropped (i.e., devices using updater3 are EOL'ed), we can:
 - remove updater3.sh
 - drop mode=startup
 - drop mode=todev
 - since the only updater is updater4 now, consider dropping UPDATER_SCRIPT and always use the single script.

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-stumpy-private/+/a6d9bc4b13da02f8c4a7f9cd00a85617641d79b4

commit a6d9bc4b13da02f8c4a7f9cd00a85617641d79b4
Author: Hung-Te Lin <hungte@chromium.org>
Date: Sat Aug 18 07:49:41 2018

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-lumpy-private/+/33a33e18eaf02cdaaf484d8f5f20a1a7258fb0e6

commit 33a33e18eaf02cdaaf484d8f5f20a1a7258fb0e6
Author: Hung-Te Lin <hungte@chromium.org>
Date: Sat Aug 18 07:49:41 2018

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-butterfly-private/+/75ed3a427d445e14e01b05ee9b52878ab8a82255

commit 75ed3a427d445e14e01b05ee9b52878ab8a82255
Author: Hung-Te Lin <hungte@chromium.org>
Date: Sat Aug 18 07:49:40 2018

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-parrot-private/+/6751ac69044dccde23b18f33fce88c320e25c88f

commit 6751ac69044dccde23b18f33fce88c320e25c88f
Author: Hung-Te Lin <hungte@chromium.org>
Date: Tue Aug 28 18:26:44 2018

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-parrot-private/+/01ca4bb8ab8b6a6bb2083155e15c1d8af6d5efb3

commit 01ca4bb8ab8b6a6bb2083155e15c1d8af6d5efb3
Author: Hung-Te Lin <hungte@google.com>
Date: Thu Aug 30 16:53:15 2018

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/firmware/+/3f37125e1b3e15172d3143e0b188e23101edf04c

commit 3f37125e1b3e15172d3143e0b188e23101edf04c
Author: Hung-Te Lin <hungte@chromium.org>
Date: Sat Sep 08 13:49:50 2018

firmware: Drop 'todev' mode.

The 'todev' was mainly used by updater v2 generation (alex, zgb; those
need to reflash a DEV firmware) and was replaced by crossystem settings
since v3, and since then replaced by enable_dev_usb_boot script in
vboot_reference repository.

We have already revised all documents to use enable_dev_usb_boot instead
of running "chromeos-firmwareupdate --mode=todev", and updater v2 has
been removed for a long time so it should be fine to drop 'todev' support.

BUG= chromium:806383 
TEST=make test

Change-Id: Ibbd7dd9a6626ea6388ca67f30d4efafd41f0f1d7
Reviewed-on: https://chromium-review.googlesource.com/1180622
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

[modify] https://crrev.com/3f37125e1b3e15172d3143e0b188e23101edf04c/pack_dist/crosutil.sh
[modify] https://crrev.com/3f37125e1b3e15172d3143e0b188e23101edf04c/pack_dist/updater4.sh
[modify] https://crrev.com/3f37125e1b3e15172d3143e0b188e23101edf04c/pack_dist/common.sh
[modify] https://crrev.com/3f37125e1b3e15172d3143e0b188e23101edf04c/pack_dist/updater3.sh

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-stout-private/+/6ad09bcc701dbef17d5e1e9d7333fd94cb23e6d0

commit 6ad09bcc701dbef17d5e1e9d7333fd94cb23e6d0
Author: Hung-Te Lin <hungte@chromium.org>
Date: Tue Oct 30 15:42:56 2018

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-parrot-private/+/458181d7005d3332738d14e9d1b1374125e6d86e

commit 458181d7005d3332738d14e9d1b1374125e6d86e
Author: Hung-Te Lin <hungte@chromium.org>
Date: Tue Oct 30 19:03:26 2018

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/firmware/+/71a517f90489ebafa322302c2b07c64b09f04930

commit 71a517f90489ebafa322302c2b07c64b09f04930
Author: Hung-Te Lin <hungte@chromium.org>
Date: Thu Nov 01 04:59:17 2018

firmware: Remove updater3.sh

The Chromebooks using updater3 are now all EOL'ed, and the updater
ebuilds are also removed from overlays, so it should be fine to finally
remove the updater3 script.

BUG= chromium:806383 
TEST=make test
CQ-DEPEND=CL:*664037, CL:*677811

Change-Id: I3992ecd026491180f28dea317965c30a96d165b5
Reviewed-on: https://chromium-review.googlesource.com/1179740
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[delete] https://crrev.com/f5d5098fa56bdc705d95218ca04a4df784f5f29e/pack/dist/updater3.sh

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/49da94ad20ce233d75ee8bf39bf0dccd14137282

commit 49da94ad20ce233d75ee8bf39bf0dccd14137282
Author: Mike Frysinger <vapier@chromium.org>
Date: Thu Nov 01 04:59:31 2018

init: chromeos-startup: drop support for firmware-boot-update

This is only used by lumpy/stumpy/butterfly/parrot/stout which are EOL.
Drop support for executing this script at startup.

BUG= chromium:806383 
TEST=precq passes

Change-Id: I5e5671a18f7cab1654ae3ce63c4b0f984f9003c0
Reviewed-on: https://chromium-review.googlesource.com/1156069
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

[modify] https://crrev.com/49da94ad20ce233d75ee8bf39bf0dccd14137282/init/chromeos_startup

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/firmware/+/844b203aec9cf2353f7d14fca5768baab524f4af

commit 844b203aec9cf2353f7d14fca5768baab524f4af
Author: Hung-Te Lin <hungte@chromium.org>
Date: Thu Nov 01 17:02:16 2018

firmware: Drop 'startup' mode (boot update) and firmware-boot-update

The 'startup' mode was mainly used for updating non-Chrome EC without
software sync, and only needed by updater v3 (already deprecated).

As a result, it should be fine to drop the 'startup' mode' and its
supporting files (firmware-boot-update*).

BUG= chromium:806383 
TEST=make test
CQ-DEPEND=CL:1310154

Change-Id: I8b2d08b43e73b6e0453e89a0fe1db2f994047cc3
Reviewed-on: https://chromium-review.googlesource.com/1180621
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[delete] https://crrev.com/2cd6f5a4299d77480847f5f27676e20aabd719d7/sbin/firmware-boot-update.3
[modify] https://crrev.com/844b203aec9cf2353f7d14fca5768baab524f4af/unittests/crosutil_unittest
[modify] https://crrev.com/844b203aec9cf2353f7d14fca5768baab524f4af/pack/dist/crosutil.sh
[modify] https://crrev.com/844b203aec9cf2353f7d14fca5768baab524f4af/pack/dist/common.sh
[modify] https://crrev.com/844b203aec9cf2353f7d14fca5768baab524f4af/pack/dist/updater4.sh
[delete] https://crrev.com/2cd6f5a4299d77480847f5f27676e20aabd719d7/sbin/firmware-boot-update
[delete] https://crrev.com/2cd6f5a4299d77480847f5f27676e20aabd719d7/sbin/README

all removed :)